1. Field of the Invention
The present invention relates to an electrode body, and more particularly, to an electrode body in which a plurality of electrodes are formed to protrude on a base member and a wiring substrate and a semiconductor device that uses the electrode body.
2. Description of Related Art
With high performance and miniaturization of systems, semiconductor devices are required to have a smaller size and high performance. Therefore, a technique called “silicon wafer direct bonding” of bonding wafers in which a plurality of minute bumps functioning as electrodes are formed has been also examined.
To electrically connect the bumps in the silicon wafer direct bonding, it is necessary to apply a load to the wafer, but the necessary load increases with the number of bumps. For example, when bumps with a diameter of about 10 μm are formed on the entire surface of a wafer of 8 inches (23.2 cm), the number of bumps is hundreds of millions, and thus the load necessary for the bonding becomes several tons.
Here, when the heights of the bumps are irregular, the load is first concentrated on the highly formed bumps, and thus there is a concern that these bumps may be damaged. For this reason, to reduce the bonding load, flattening the upper surfaces of the bumps by grinding, chemical mechanical polishing (CMP), or the like has been investigated. However, flattening the hundreds of millions of bumps uniformly without any damage to the bumps is not easy, and there is a concern with the delivery and the cost.
In regard to this problem, Patent Literature 1 discloses a method of forming minute uneven portions on the upper surfaces of the bumps using a pressing device. The formed minute uneven portions serve as crushing margins that absorb the height irregularity of the bumps, and thus the load necessary for the bonding is considered to be reduced.
[Patent Literature 1] Japanese Unexamined Patent Application, First Publication No. 2001-267371